Insects and disease can insidiously damage or destroy vegetation, including, for example, grapefruit, oranges, and other citrus fruits. To minimize the effects of such plagues, fruit trees are frequently treated with fungicides, pesticides, and other chemicals of varying types. If grown in groves, the trees are often treated using existing commercial sprayers, which can be hitched to tractors and passed between rows of trees in a grove. Spraying chemicals from both the left and right sides of the sprayer permits it to treat concurrently at least portions of trees in two adjacent rows.
Existing agricultural sprayers do not uniformly treat exposed surfaces of fruits and foliage, however. Many such commercial sprayers include only a single opening or an air stream per side and provide solely high volume air as a fluid propellant. Generally, therefore, if these sprayers travel at high speeds, they inadequately supply the inner canopies of the vegetation, leaving such areas vulnerable to pests and disease. Conversely, slow travel through vegetation typically sacrifices uniform coverage of the outer foliage. In either event, the high volume air used by these sprayers typically causes the chemical spray to contact exposed sides of the fruit near the outer canopies and continue through the trees, precluding the spray from covering the rear (non-exposed) surfaces of the fruit.
U.S. Pat. No. 2,686,990 to Matthews, incorporated herein in its entirety by this reference, discloses another horticultural sprayer. Unlike sprayers currently in commercial use, the sprayer disclosed in the Matthews patent purportedly attempts to provide coverage for the rears of leaves and twigs. To do so the sprayer uses duplicate blowers and associated nozzles angled "so that the blasts of air emanating from these nozzles will be directed in converging paths meeting with each other either laterally or vertically of the vehicle, as the case may be." According to the Matthews patent, these converging blasts bend tree branches alternately clockwise and counterclockwise (or vice-versa) as the vehicle passes, allegedly to deposit spraying material uniformly on the surfaces of the foliage.
Although the nozzles disclosed in the Matthews patent can be tilted upwardly for taller foliage or rotated to either side of the apparatus especially for smaller trees, they cannot otherwise be adjusted to avoid disturbing the required angular convergence of the air streams. The interdependent air streams themselves, moreover, are both of the same velocity to penetrate and converge at the center (i.e. trunk) of each tree, as shown in FIG. 8 of the Matthews patent. As a result, the apparatus of the Matthews patent neither supplies multiple streams of differing velocities and volumes nor creates eddy currents at the outer canopies of trees.